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    Building, troubleshooting and testing of these amplifiers should only be
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#26 pre amp

For quite some time ,I am now using the AZ1 Valvo meshplate, they are fabulous !
You shuld try the AZ1 or AZ11 , get the big meshplate versions, the biggest meshplates are from Valvo, Philips , then comes Lorenz , Telefunken and others with smaller dimensions.

Funny that bigger meshplates do contribute significantly towards better blooming, staging and transparancy of sound. Better even than the 80/83 mercury which I found a bit troublesome as we hav to install a separate toggle switch to switch on the B+ after the tube is sufficiently hot.

In addition I tried the 80 mercury and found the noisy and rather grainy, but yes they are better than the ordinary solidplate rectifiers.

Yu can try out the 83V (non mercury) Sylvania,RCA,Cunninghams which in my opinion are the best solid plate verwsions made by US.

Just my 2cents
Regards
Paul
 
For quite some time ,I am now using the AZ1 Valvo meshplate, they are fabulous !
You shuld try the AZ1 or AZ11 , get the big meshplate versions, the biggest meshplates are from Valvo, Philips , then comes Lorenz , Telefunken and others with smaller dimensions.

Funny that bigger meshplates do contribute significantly towards better blooming, staging and transparancy of sound. Better even than the 80/83 mercury which I found a bit troublesome as we hav to install a separate toggle switch to switch on the B+ after the tube is sufficiently hot.

In addition I tried the 80 mercury and found the noisy and rather grainy, but yes they are better than the ordinary solidplate rectifiers.

Yu can try out the 83V (non mercury) Sylvania,RCA,Cunninghams which in my opinion are the best solid plate verwsions made by US.

Just my 2cents
Regards
Paul

Hi Paul,

Thanks for the tips. But it is hard to find those mesh plates. Does the solid plate AZ1 does the same? Those seems available freely. Any other suggestions? I'd like to experiment on this a bit.
 
Please could tell me the post where is the final schematic with BOM & regs + psu requirements?

Thank you

Below is the link for my existing gird bias schematic.

http://www.diyaudio.com/forums/tubes-valves/151421-26-pre-amp-36.html (check the thread 353)

Use Salas HV supply for the B+. Find the details in the below link.

http://www.diyaudio.com/forums/quan...hono-tube-pre-simplistic-mosfet-hv-shunt.html

You could contact Salas for more details of PSU. Probably if you speak to quanghao , you might get the hold of the PCB for this.

For filament supply, use Rod Coleman's PSU. Contact Rod to get the parts and PCB for a very reasonable price. As well his kind support for free.:)
http://www.diyaudio.com/forums/tubes-valves/151421-26-pre-amp-62.html

You are done and end up with an excellent 26 pre after all this.:D Good luck.
 
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Below is the link for my existing gird bias schematic.

http://www.diyaudio.com/forums/tubes-valves/151421-26-pre-amp-36.html (check the thread 353)

Use Salas HV supply for the B+. Find the details in the below link.

http://www.diyaudio.com/forums/quan...hono-tube-pre-simplistic-mosfet-hv-shunt.html

You could contact Salas for more details of PSU. Probably if you speak to quanghao , you might get the hold of the PCB for this.

For filament supply, use Rod Coleman's PSU. Contact Rod to get the parts and PCB for a very reasonable price. As well his kind support for free.:)
http://www.diyaudio.com/forums/tubes-valves/151421-26-pre-amp-62.html

You are done and end up with an excellent 26 pre after all this.:D Good luck.

Thanks so much.

Sorry for my ignorance what are OA2 & OB3 in the schematic? Wich tubes do you recommend for 5Y4GT & 26?
 
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Thanks so much.

Sorry for my ignorance what are OA2 & OB3 in the schematic? Wich tubes do you recommend for 5Y4GT & 26?

OA2/OB3 are Zener tubes used to regulate the B+. You don't need those if you use SALAS HV PSU for B+. Ignore the power supply in my schematic fully if you are planing to use SALAS and replace that part with SALAS PSU.

I strongly recommend to use type 80 over 5Y4 or 5Y3 for the rectifier or if you could find a mesh plate AZ1 as someone recommended in this thread. Brand of the tube could be anything of US or UK made once.

For 26, I liked Silvertone, Sylvania and Cunningham over others.
 
Below is the link for my existing gird bias schematic.
QUOTE]

I'm not sure the battery grid bias would work with Colemean's filament supply, has anyone tried this?

Regal, I fixed Rod's fil.PSU to my gird bias 26. It is working so far perfectly without an issue. Rod advised me to ground the supply only at the 26 pin (1 or 4). I think this is the only concern.
 
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Member
Joined 2009
Paid Member
OA2/OB3 are Zener tubes used to regulate the B+. You don't need those if you use SALAS HV PSU for B+. Ignore the power supply in my schematic fully if you are planing to use SALAS and replace that part with SALAS PSU.

I strongly recommend to use type 80 over 5Y4 or 5Y3 for the rectifier or if you could find a mesh plate AZ1 as someone recommended in this thread. Brand of the tube could be anything of US or UK made once.

For 26, I liked Silvertone, Sylvania and Cunningham over others.

Thank you again:)
 
Regal, I fixed Rod's fil.PSU to my gird bias 26. It is working so far perfectly without an issue. Rod advised me to ground the supply only at the 26 pin (1 or 4). I think this is the only concern.

Battery bias, fixed bias, cathode bias - any bias method works with the new Regulator.

As Kanishka says, you just have to be sure to only have ONE ground return for the anode current - pin 1 or 4 of the tube socket.
 
Hi Coolzero,
Go to the German Ebay site : eBay: Neue und gebrauchte Elektronikartikel, Autos, Kleidung, Sammlerstücke, Sportartikel und mehr ? alles zu günstigen Preisen
then search for AZ1
Yu can see various AZ1 , then solid plates and the meshplates.

Yu also can use the AZ11 or AZ12 in liaue of the AZ1. they hav the same specs.

Thou the AZ solidplates are superior to the "standard" retifiers tube (ie. GZ34/32, 5AR4, 83V etc..) the AZ solid plates are significantly way behind the meshplates.

Paul
 
Hi,

I have fixed Rod's filament PSU, rewired my pre amp and it sounds great now. But one small issue remains it seems. I noticed that my speaker cones are rumbling even when there is no input signal provided. No audible hum at the moment from the speaker unless I keep my ears very close to the speakers. My speaker are with 90 DB/111 SPL sensitivity. With doubts, I checked the pre out using a multimeter and observed a little bit of residual DC. I assume the speaker rumble is because of the DC coming out of the pre. All my coupling caps are brand new Mundorf hence I wouldn't expect any sort of leak from those. Is my assumption correct? Or else, is there any other reason for this? How I can get rid of this issue? Appreciate your advice as usual.
 
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I checked the pre out using a multimeter and observed a little bit of residual DC :
can be a fake reading...try misure dc current.
I haved problem with pumping cone changing psu coke with hight resistence in my tube amp,ie the clc frequency of psu ....
 
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